Answer
For handrail before polyurethane, use 180 then 220. Between cured coats, scuff with 320 or 400.
Why it happens
Handrails get oils and wear from hands, so the surface must be clean, smooth, and evenly scuffed before finish.
Recommended grit
Use 180 then 220 before the first coat. Use 320 or 400 lightly between cured coats.
Wet or dry
Dry.
Success check
The handrail is smooth, clean, and evenly prepared before finish.
What to do
- Clean hand oils from the rail.
- Sand bare wood with 180 then 220.
- Apply polyurethane after dust removal.
- Scuff cured coats lightly with 320 or 400.
Avoid: Do not apply polyurethane over oily or dusty handrail surfaces.